<template>
    <div>
        <div id="shopcart" class="shopcart">
            <div class="content" @click="toggleList">
                <div class="content-left">
                    <div class="logo-wrapper">
                        <div class="logo" :class="{highlight:totalCount>0}">
                            <i class="icon-shopping_cart" :class="{highlight:totalCount>0}"></i>
                        </div>
                        <div class="num" v-show="totalCount>0">{{totalCount}}</div>
                    </div>
                    <div class="price" :class="{highlight:totalPrice>0}">￥{{totalPrice}}</div>
                    <div class="desc">另需配送费￥{{deliveryPrice}}元</div>
                </div>
                <div class="content-right" @click.stop.prevent="pay">
                    <div class="pay" :class="payClass">
                        {{payDesc}}
                    </div>
                </div>
            </div>
            <div class="ball-container">
                <div v-for="(ball, index) in balls" :key="index">
                    <transition name="drop" @before-enter="beforeDrop" @enter="dropping" @after-enter="afterDrop">
                        <div class="ball" v-show="ball.show">
                            <div class="inner inner-hook"></div>
                        </div>
                    </transition>
                </div>
            </div>
            <transition name="fold">
                <div class="shopcart-list" v-show="listShow">
                    <div class="list-header">
                        <h1 class="title">购物车</h1>
                        <span class="empty" @click="empty">清空</span>
                    </div>
                    <div class="list-content" ref="listContent">
                        <ul>
                            <li class="food" v-for="(food, index) in selectedFoods" :key="index">
                                <span class="name">{{food.name}}</span>
                                <div class="price">
                                    <span>￥{{food.price*food.count}}</span>
                                </div>
                                <div class="cartcontrol-wrapper">
                                    <cart-control @add="addFood" :food="food"></cart-control>
                                </div>
                            </li>
                        </ul>
                    </div>
                </div>
            </transition>
        </div>
        <transition name="fade">
            <div class="list-mask" @click="hideList" v-show="listShow"></div>
        </transition>
    </div>
</template>

<script>
import BScroll from 'better-scroll';
import CartControl from '../cartcontrol/cartcontrol';

export default {
    name: 'shopcart',
    props: {
        selectedFoods: {
            type: Array,
            default() {
                return [
                    {
                        price: 0,
                        count: 0
                    }
                ];
            }
        },
        deliveryPrice: {
            type: Number,
            default: 0
        },
        minPrice: {
            type: Number,
            default: 0
        }
    },
    data() {
        return {
            balls: [
                {
                    show: false
                },
                {
                    show: false
                },
                {
                    show: false
                },
                {
                    show: false
                },
                {
                    show: false
                },
                {
                    show: false
                },
                {
                    show: false
                },
                {
                    show: false
                },
                {
                    show: false
                },
                {
                    show: false
                },
                {
                    show: false
                },
                {
                    show: false
                }
            ],
            dropBalls: [],
            fold: true
        };
    },
    methods: {
        pay() {
            if (this.totalPrice < this.minPrice) {
                return;
            }
            window.alert('一共' + this.totalPrice + '元');
        },
        hideList() {
            this.fold = true;
        },
        toggleList() {
            if (!this.totalCount) {
                return;
            }
            this.fold = !this.fold;
        },
        empty() {
            this.selectedFoods.forEach(function (food) {
                food.count = 0;
            }, this);
        },
        addFood(target) {
            console.log('addFood');
            this.drop(target);
        },
        drop(el) {
            //找到show为false的小球
            for (let i = 0; i < this.balls.length; i++) {
                let ball = this.balls[i];
                if (!ball.show) {
                    ball.show = true;//触发动画
                    ball.el = el;
                    this.dropBalls.push(ball);
                    return;
                }
            }
        },
        beforeDrop(el) {
            //遍历所有小球 添加动画
            for (let i = 0; i < this.balls.length; i++) {
                let ball = this.balls[i];
                if (ball.show) {
                    //找到add按钮在视口的位置
                    let rect = ball.el.getBoundingClientRect();
                    //计算x和y方向差距
                    let x = rect.left - 32;
                    let y = -(window.innerHeight - rect.top - 22);
                    // console.log(x, y);
                    el.style.display = '';
                    el.style.webkitTransform = `translate3d(0,${y}px,0)`;
                    el.style.transform = `translate3d(0,${y}px,0)`;
                    let inner = el.getElementsByClassName('inner-hook')[0];
                    inner.style.webkitTransform = `translate3d(${x}px,0,0)`;
                    inner.style.transform = `translate3d(${x}px,0,0)`;
                }
            }
        },
        dropping(el, done) {
            /*当获取一些属性时，浏览器为取得正确的值也会触发重排。这样就使得浏览器的优化失效了。
            这些属性包 括：offsetTop、offsetLeft、 offsetWidth、offsetHeight、scrollTop、scrollLeft、
            scrollWidth、scrollHeight、 clientTop、clientLeft、clientWidth、clientHeight、
            getComputedStyle() (currentStyle in IE)。所以，在多次使用这些值时应进行缓存。*/
            let rf = el.offsetHeight;
            this.$nextTick(() => {
                el.style.webkitTransform = 'translate3d(0,0,0)';
                el.style.transform = 'translate3d(0,0,0)';
                let inner = el.getElementsByClassName('inner-hook')[0];
                inner.style.webkitTransform = 'translate3d(0,0,0)';
                inner.style.transform = 'translate3d(0,0,0)';
                el.addEventListener('transitionend', done);
            });
        },
        afterDrop(el) {
            let ball = this.dropBalls.shift();
            if (ball) {
                ball.show = false;
                el.style.display = 'none';
            }
        }
    },
    computed: {
        listShow() {
            if (!this.totalCount) {
                this.fold = true;
                return false;
            }
            let show = !this.fold;
            if (show) {
                this.$nextTick(() => {
                    if (!this.scroll) {
                        this.scroll = new BScroll(this.$refs.listContent, {
                            click: true
                        });
                    } else {
                        this.scroll.refresh();
                    }
                });
            }
            return show;
        },
        totalPrice() {
            let total = 0;
            this.selectedFoods.forEach(function (food) {
                total += food.price * food.count;
            }, this);
            return total;
        },
        totalCount() {
            let total = 0;
            this.selectedFoods.forEach(function (food) {
                total += food.count;
            }, this);
            return total;
        },
        payDesc() {
            if (this.totalPrice === 0) {
                return `￥${this.minPrice}元起送`;
            } else if (this.totalPrice < this.minPrice) {
                let diff = this.minPrice - this.totalPrice;
                return `还差￥${diff}元起送`;
            } else {
                return `去结算`;
            }
        },
        payClass() {
            return {
                enough: this.totalPrice >= this.minPrice,
                'not-enough': (this.totalPrice !== 0) && (this.totalPrice < this.minPrice)
            };
        }
    },
    components: {
        CartControl
    }
}
</script>

<style lang="less" scoped>
@import '../../common/styles/mixin.less';

.shopcart {
    position: fixed;
    bottom: 0;
    left: 0;
    z-index: 50;
    width: 100%;
    height: 48px;

    .content {
        display: flex;
        background: #141d27;
        font-size: 0;
        color: rgba(255, 255, 255, 0.4);
        .content-left {
            flex: 1;
            .logo-wrapper {
                display: inline-block;
                vertical-align: top;
                position: relative;
                top: -10px;
                margin: 0 12px;
                padding: 6px;
                height: 56px;
                width: 56px;
                box-sizing: border-box;
                border-radius: 50%;
                background: #141d27;
                .logo {
                    width: 100%;
                    height: 100%;
                    border-radius: 50%;
                    text-align: center;
                    background: #2b343c;
                    &.highlight {
                        background: #00a0dc;
                    }
                    .icon-shopping_cart {
                        line-height: 44px;
                        font-size: 24px;
                        color: #80858a;
                        &.highlight {
                            color: #fff;
                        }
                    }
                }
                .num {
                    position: absolute;
                    top: 0;
                    right: 0;
                    width: 24px;
                    font-size: 9px;
                    font-weight: 700;
                    color: rgb(255, 255, 255);
                    line-height: 16px;
                    background-color: rgb(240, 20, 20);
                    text-align: center;
                    border-radius: 8px;
                    box-shadow: 0px 4px 8px 0px rgba(0, 0, 0, 0.4);
                }
            }
            .price {
                display: inline-block;
                vertical-align: top;
                margin-top: 12px;
                padding-right: 12px;
                line-height: 24px;
                box-sizing: border-box;
                border-right: 1px solid rgba(255, 255, 255, 0.1);
                font-size: 16px;
                font-weight: 700;
                &.highlight {
                    color: #fff;
                }
            }
            .desc {
                display: inline-block;
                vertical-align: top;
                margin-top: 12px;
                margin-left: 12px;
                font-size: 10px;
                line-height: 24px;
            }
        }
        .content-right {
            flex: 0 0 105px;
            width: 105px;
            .pay {
                background: #2b333b;
                height: 48px;
                line-height: 48px;
                text-align: center;
                font-size: 12px;
                font-weight: 700;
            }
            .enough {
                background: #00b43c;
                color: #fff;
            }
            .not-enough {
                background: #2b333b;
            }
        }
    }

    .ball-container {
        .ball {
            position: fixed;
            left: 32px;
            bottom: 22px;
            z-index: 200;
            transition: all 0.4s cubic-bezier(0.49, -0.29, 0.75, 0.41);
            .inner {
                width: 16px;
                height: 16px;
                border-radius: 50%;
                background: rgb(0, 160, 220);
                transition: all 0.4s linear;
            }
        }
    }

    .shopcart-list {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        z-index: -1;
        transform: translate3d(0, -100%, 0);
        &.fold-enter-active,
        &.fold-leave-active {
            transition: all 0.5s;
        }

        &.fold-enter,
        &.fold-leave-to {
            transform: translate3d(0, 0, 0);
        }

        .list-header {
            height: 40px;
            line-height: 40px;
            background: #f3f5f7;
            font-size: 0;
            border-bottom: 1px solid rgba(7, 17, 27, 0.1);
            .title {
                float: left;
                font-size: 14px;
                font-weight: 200;
                color: rgb(7, 17, 27);
                margin-left: 18px;
            }
            .empty {
                float: right;
                font-size: 12px;
                color: rgb(0, 160, 220);
                margin-right: 18px;
            }
        }

        .list-content {
            background: #fff;
            max-height: 217px;
            overflow: hidden;
            padding: 0 18px;
            .food {
                position: relative;
                padding: 12px 0;
                box-sizing: border-box;
                .border-1px(rgba(7, 17, 27, 0.1));
                .name {
                    font-size: 14px;
                    color: rgb(7, 17, 27);
                    line-height: 24px;
                }
                .price {
                    position: absolute;
                    bottom: 12px;
                    right: 90px;
                    line-height: 24px;
                    font-size: 14px;
                    font-weight: 700;
                    color: rgb(240, 20, 20);
                }
                .cartcontrol-wrapper {
                    position: absolute;
                    right: 0;
                    bottom: 6px
                }
            }
        }
    }
}

.list-mask {
    position: fixed;
    z-index: 49;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    background: rgba(7, 17, 27, 0.6);
    backdrop-filter: blur(10px);
    opacity: 1;
    &.fade-enter-active,
    &.fade-leave-active {
        transition: all 0.5s;
    }
    &.fade-enter,
    &.fade-leave-to {
        opacity: 0;
        background: rgba(7, 17, 27, 0);
    }
}
</style>
